Specific Intracellular Signature of SARS-CoV-2 Infection Using Confocal Raman Microscopy

Abstract

SARS-CoV-2 infection remains to spread worldwide and requires a better understanding of virus-host interactions. Here, we analyzed biochemical modifications due to SARS-CoV-2 infection in cells by confocal Raman microscopy. Obtained results were compared with the infection with another RNA virus, the measles virus. Our results have demonstrated a virus-specific Raman hallmark of molecular signature, reflecting intracellular modification during each infection. Advanced data analysis has been used to distinguish non-infected versus infected cells for two RNA viruses. Further, classification between non-infected and SARS-CoV-2 and measles virus-infected cells yielded an accuracy of 98.9 and 97.2 respectively, with a significant increase of the essential amino-acid tryptophan in SARS-CoV-2-infected cells. These results present proof of concept for the application of Raman spectroscopy to study virus-host interaction and to identify factors that contribute to the efficient SARS-CoV-2 infection and may thus provide novel insights on viral pathogenesis, targets of therapeutic intervention and development of new COVID-19 biomarkers.

Raman spectroscopic cellomics for the detection of SARS‐CoV‐2‐associated neutrophil activation after TNF‐α stimulation

“…The tryptophan metabolism pathway plays a crucial role in inflammation and immune tolerance captured in Raman spectra. 7 Our findings indicate a respond of neutrophil granulocytes to SARS-CoV-2 by producing antiviral and inflammatory substances, including IP-10 and IL-6, identified as an independent predictor for disease progression. 1,2 In addition, pre-stimulation by TNF-α and LPS results in increased expression of the measured cytokines.…”

“…4 Compared to traditional flow cytometry, this spectrum displays the sample's label-free molecular signature, which is susceptible to change due to biological stimulations. [5][6][7] Machine learning approaches are applied to transfer the spectral into meaningful biological information. 8 It is well-established that neutrophil granulocytes require pre-stimulation to induce their inflammatory capacity.…”

“…3 High throughput screening RS (HTS-RS) represents an innovative strategy for direct and non-destructive detection of changes in the composition and phenotype of the white blood cells. [4][5][6][7] The principle of this technique is to irradiate a cell with laser light for a few seconds and record the inelastically scattered light as a spectrum. 4 Compared to traditional flow cytometry, this spectrum displays the sample's label-free molecular signature, which is susceptible to change due to biological stimulations.…”